2009-01-10 11:31:12

by Dmitry Baryshkov

Subject: Network device with variable hard header len

Hi,

Sorry if this a dumb question. Currently I'm programming a driver for
the devices with variable network header len. From the Linux net stack
perspective what should I do: set netdev->hard_header_len to maximum
possible header and use less space that specified there or set
netdev->needed_headroom to that value?

If that metters, I'll be implementing my own set of header_ops in any
case.

Thank you

--
With best wishes
Dmitry

2009-01-12 12:07:35

by Mark Brown

Subject: Re: Network device with variable hard header len

On Sat, Jan 10, 2009 at 02:28:12PM +0300, Dmitry Eremin-Solenikov wrote:

> Sorry if this a dumb question. Currently I'm programming a driver for
> the devices with variable network header len. From the Linux net stack
> perspective what should I do: set netdev->hard_header_len to maximum
> possible header and use less space that specified there or set
> netdev->needed_headroom to that value?

> If that metters, I'll be implementing my own set of header_ops in any
> case.

This is probably better asked on netdev (CCed).